msm: mdss: hdmi: adjust audio clock frequency for YUV modes

The audio clock frequency for a given YUV mode must be scaled at the
same ratio as the pixel clock when programming the hardware for
audio transmission. This will ensure that the video and audio
data for YUV modes are transmitted at the same rate, and ensure
smooth playback on the sink.

Change-Id: I9405a0e0e39405c5c287e3e8a764d5c21bb42adb
Signed-off-by: Tatenda Chipeperekwa <tatendac@codeaurora.org>